Physiology Flashcards
what are the three types of muscle
skeletal, cardiac and smooth
Which muscles are striated?
skeletal and cardiac
what produces the dark band under microscope
myosin
what are skeletal muscles innervated by
somatic nervous system
is cardiac muscles innervated by autonomic or somatic nervous system?
Autonomic
What is a motor unit
single alpha motor neurone and all the fibres it innervates
True or false, the more fibres per motor unit results in increased precision
False, increased fibres per motor unit result in increased strength
how is the cardiac and skeletal muscle initiated?
cardiac- myogenic, skeletal- neurogenic
Where does Ca come from in skeletal muscle?
ALL from sarcoplasmic reticulum
What is the transmitter at the neuromuscular junction
acetylcholine
How are muscles attached to skeleton?
tendons
What are myofibrils
specialised contractile intracellular structures
What are actin and myosin arranged into
Sarcomeres
What is the A zone
length of the thick filaments which includes some thin filaments
what is the H zone
lighter area where thin filaments font get to
What is the m line
extends vertical down A band within H zone
WHAT IS THE I ZONE
thin filaments that do not participate in the A band
What does actin and myosin require?
Ca (for switching on ) and ATP for relaxation and contraction
what does the gradation of muscle tension depend on
number of muscle fibres contracting in muscle, tension developed by each contracting muscle fibre
Is the duration of the action potential longer or shorter than the resulting twitch
shorter
What is summation
addition of one twitch before the previous one has relaxed results in double contractile activity
What is a tetanus
when muscle fibres contract time after time producing a maximum sustained contraction
What does maximal contraction depend on?
initial length of skeletal muscle from outset
What are the 2 types of contractile muscle called
isotonic and isometric
What is isometric contractions used for
supporting objects in fixed positions and maintaining body posture
How is muscle tension transmitted to bone
elastic components of muscle
Name some causes of intrinsic muscle disease
congenital myopathies, muscular dystrophy, myotoniapolymyosytis, cushing syndrome, alcohol and steroids
Stretch reflex is the simplest…
monosynaptic spinal reflex
what are muscle spindles
sensory receptors for stretch reflex- collection of specialised muscle fibres
do muscle spindles run parallel or opposition to ordinary muscle fibres
parallel
what are the sensory nerve endings called
annulospiral
what are the efferent neutrons called g
gamma motor neurons
what do the gamma motor neurone do?
adjust tension level to sustain sensitivity when muscles shorten during muscle contraction
what source of ATP is used when O2 is not present
glycolysis
what are type 1 fibres used for
slow twitch, prolonged activity i.e. walking
what are type 2a fibres used for
fast twitch fibres, short term high intensities i.e. jumping
Investigations in MSK
creatine kinase enzyme, electromyography, nerve conduction studies
Do fibrous joint allow movements
no
Where would you find a cartilaginous joint in the body?
intervertebral discs
What are bones separated by
joint cavity
what are bones united by?
fibrous capsule
what does the synovial membrane produce
synovial fluid
What are simple synovial joints?
only one pair of articular surfaces present
What is a compound synovial joiojtn
Where there is more than 1 articulation i.e. at the elbow
What is the joint lubricated by?
cartilage interstital fluid, hyaluronic acid, glycoproteins
Does synovial fluid have a high viscosity?
Yes- due to the presence of the hyaluronic acid
rapid movement is associated with…(viscosity and elasticity)
Increased elasticity and decreased viscosity
when des the synovial fluid turn red?
In traumatic event snad haemorrhagic arthritis
what is the bottom layer of the cartilage called?
calcified zone
what is the main type of cartilage?
hyaline
which type of collagen contributes most to the special ECM
collagen type 2
What 3 things make up the cartilage
water (70%), collagen type 2 (20%) and proteoglycans (10%)
What 2 things lead to catabolic cartilage
IL2 and Tumour necrosis factor
What promotes regenration of cartilage
tumour growth factor and insulin like growth factor
How could you determine cartilage degradation
serum and synovial keratin sulphate- increased levels= cartilage breakdown type 2 collagen in synovial fluid- increased= cartilage breakdown
What does synovial cell proliferation and inflammation lead to?
rheumatic arthritis
what sign leads to gouty arthritis
deposition of salt crystals
osteoarthritis occurs because…
wear and tear and cartilage decomposition
What is gout?
defective metabolism of uric acid which causes arthritis espesh in small bones of the feet
Name seropositive arthropathies (5)
SLE, Sjogrens, rheumatoid arthritis, vasculitis, scleroderma
what are seronegative arthropathies
ankylosing spondylitis, psoriatic arthritis, reactive arthritis, inflammatory bowel disease
